1. Field of Invention
The present invention relates to a lighting apparatus, in particular in the form of ceiling spots, with a perforated panel having at least one aperture for light to pass through, as well as a lens arranged to as to be concealed behind the perforated lens to emit a bundle of light beams that narrows on its way from the lens to the perforated panel, passes through the aperture for light to pass through, and broadens against after leaving the perforated panel.
2. Background and Related Art
Such a lighting apparatus is known from EP 20 31 296 A1, and is sometimes known as a recessed spotlight. In this apparatus, lighting means are covered by flat coverings in the form of perforated panels and arranged such as to be invisible to the human eye, where the aforementioned perforated panels may form a wall or ceiling covering, e.g. in the manner of a suspended ceiling. In order for the light produced by the lighting means to be emitted through the relatively small apertures for light to pass through, lenses are provided for the lighting means that capture the light emitted from the lighting means and bundle it into a roughly hourglass-shaped bundle of light beams, which narrows on its way from the light emitting surface of the lens to the perforated panel to the point that it is able to pass through the aperture for light to pass through, and broadens again after passing through the aperture on the front side of the perforated panel. As a result, the apertures for light to pass through can be kept very small in order to conceal from view the lenses and lighting means, which can be arranged spaced at a distance from the back side of the perforated panel, and prevent a glaring effect from looking directly into the lighting means.
Due to the limited space available behind the perforated panel—minimizing the distance to the ceiling or wall behind it is intended to also minimize the ceiling height or room volume lost—and the often dense, grid-like array of multiple apertures for light to pass through, the lenses must be of a compact design. As the diameter of the apertures for light to pass through must also be very small, which requires the precise capture of the bundle of light beams and an exact alignment of the bundle of light beams toward the aperture for light to pass through, the lenses mentioned below have thus far been sensitive in terms of the positioning of the lighting means relative to the light entering interface of the lenses. Manufacturing tolerances when installing the lenses on the lighting means, usually in the form of LEDs, can result in an irregular, patchy radiation field with areas of light and darkness and color shifts, and consequently to a correspondingly uneven illumination of the room. Similar problems may also arise due to manufacturing tolerances during production of the lenses, which can result in irregularities in the form of the lenses themselves.
Such installation and manufacturing tolerances may occur in particular when commercially available standard LED components are used which already have a dome-shaped primary lens over the chip, or may be exposed or overmolded LED chips, and are themselves quite inexpensive, but must subsequently be mounted on the lenses functioning as secondary lenses, by means of which the light is formed into a bundle of light beams that fits through the apertures in the perforated panel for light to pass through in the manner described. Furthermore, the low price of such LED components is often accompanied by a need to work with different types of LEDs from different manufacturers for different illumination tasks, depending on the intended use and application and perceptional psychology requirements or simply at the behest of client, e.g. in order to attain a specific luminous color or color temperature in the room lighting. In particular, positioning tolerances may occur that displace the LED chips off-center to the central axis of the lens or away from the theoretically ideal set point and amplify the abovementioned problems of uneven light propagation, a patchy radiation field with light and dark areas, and color shifts.
Given the above, the problem addressed by the present invention is the creation of an improved lighting apparatus of the type stated above which avoids the drawbacks of the prior art and advantageously develops it further. In particular, even room lighting is to be achieved with an arrangement of lenses less challenging in terms of its manufacture and installation, which nonetheless, despite the challenging installation environment behind a perforated panel with narrow apertures for light to pass through, enables simple adjustment of luminous color or color temperature as desired while maintaining even illumination and using standard lighting means.